I'am also ready to build the same press from the same book, I will be using 4x4 sq. tubing. I have made large power hammers with 4x4 and have not had any problems with it.
Dear moose 65 if I had your address I would make and send you a good burner for your forge . I make 3 different kinds, they all work good. the best is the forced air burner , it is wicked.